Gas-industry report claims wind-energy standards lead to pollution

A new report from Colorado's natural gas industry says increased use of wind energy indirectly results in raised pollution levels produced by some coal-fired power plants along the Front Range.

Critics say the report, released Monday, is flawed.

The report recommends curbing the use of wind energy during the next one or two years to levels that match power output at existing natural gas-fired power plants -- and building more natural gas plants in the long term.

The report -- titled "How Less Became More: Wind, Power and Unintended Consequences in the Colorado Energy Market" -- was done by Bentek Energy LLC, an Evergreen-based consulting company, for the Independent Petroleum Association of Mountain States, a trade group for the Rocky Mountain oil and gas industry.

The report may have national implications, as more states require increasing the use of renewable energy resources such as the wind and the sun, and as Congress contemplates a national renewable energy goal. The report's authors said its conclusions about Colorado were mirrored in an analysis they did of wind power use, power plant operations and emissions levels in Texas.

The report delved into four years of emissions data from individual power plants owned by Xcel Energy Inc. in Colorado. Emissions levels are reported to the federal government on an hour-by-hour basis.

The report found that when the wind picks up, which in Colorado is often at night, utilities must use it in order to comply with the state's renewable energy standards. On March 22, Gov. Bill Ritter signed a law that raised the standard from 20 percent of Xcel's power supplies to 30 percent by 2020.

But using wind power requires Xcel to cut back operations at other power plants, such as natural gas and coal, to meet the renewable-energy percentage standard, the report said. Utilities must balance electricity output from various power plants because the power can't be stored in giant batteries for use at a later time.

Cycling operations at coal plants -- ramping them up or down in response to the wind or other issues -- causes them to run less efficiently and also interferes with emissions control equipment. Those two factors, in turn, drive up the amount of sulfer dioxide, (SO2) nitrous oxide (NO2) and carbon dioxide (CO2) the coal power plants are putting out for every megawatt of energy produced, said Porter Bennett, Bentek's president.

"It's not the wind that's doing it; it's what the wind energy is causing in behavior changes at the plants," Bennett said.

Unlike coal plants, natural gas plants are designed to ramp up and down, according to the report.

Also Monday, Ritter signed HB 1365, the "Clean Air-Clean Jobs Act," which will require Xcel to cut NO2 emissions by up to 80 percent at several Front Range coal plants, covering about 900 megawatts of power, by the end of 2017. The act aims to put a plan in place to tackle ozone and haze issues before federal regulators step in.

Xcel will file a plan by Aug. 15 with state regulators on how it will retrofit coal-fired power plants, shut them down, or switch them to run on natural gas to reduce emissions levels.

Bennett said the new law is a "step in the right direction, but it's just a step. It will take care of the situation that exists today, [but] it won't provide for enough [natural] gas capacity to handle all for the expansion of wind to a 30 percent standard," the law Ritter signed on March 22.

In Washington, the American Wind Energy Association (AWEA) took aim at the report Monday, saying that the same hour-by-hour emissions data used by the IPAMS-commissioned report shows that Colorado's emissions levels dropped statewide between 2007 and 2008, even as wind power grew by 3.6 percent in the state at the same time.

"The aggregate numbers are what they are," said Michael Goggin, AWEA's manager of transmission issues. "When you're adding wind power, a zero-emissions resource to the grid, that power has to displace some of that other power. You're driving off coal or natural gas. Wind is displacing fossil fuel generation and it's a zero-emission resource."

Bennett said AWEA's numbers are true -- but misleading.

Emissions levels statewide did decline in those years, partially due to new emissions control equipment that Xcel added to its Comanche coal-fired power plant in Pueblo as part of an agreement to expand the plant, Bennett said.

"One of the points of our study is that you can't look at aggregated data; you have to go down and look deeper because the aggregation masks the real reality," Bennett said.

Xcel spokesman Mark Stutz said Monday the utility hasn't had a chance to review the final study.

In March, Xcel and representatives of the local Environmental Defense Fund chapter and Boulder-based Western Resource Advocates (WRA), which works on environmental issues, said they had attended presentations about the draft report, but were skeptical about its conclusions, and looked forward getting more information about the study.

John Nielsen, director of WRA's energy program, said in March he thought there were two "serious flaws" in the draft study:

• The analysis didn't include operations and emissions at power plants that supply power to Xcel, and its customers, in Colorado, but which aren't owned by Xcel.

• Power plants might be ramped up and down due to a number of issues -- such as maintenance at the individual plant or another plant, congestion on transmission lines or other reasons. Also, extrapolating the impact of a few windy days across an entire year could throw off conclusions, he said.

Vickie Patton, the Boulder-based deputy general counsel for the Environmental Defense Fund who works on clean-air programs for the advocacy group, said in March that she also thought the report was flawed and didn't consider overall health and air quality benefits gained from using renewable energy.